Antibodies have been site-specifically covalently cross-linked with a newly synthesized class of compounds which act as bis-affinity-labeling hapten. These oligomers of IgG are used as model immune complexes. They are separated by size and the biological properties of the sized oligomers are studied. Properties presently under study include complement fixaton and Clq binding and biological survival. BIBLIOGRAPHIC REFERENCE: Plotz, P.H.: Bivalent affinity-labeling haptens in the formation of model immune complexes. Methods in Enzymology 46:505-508, 1977.